Conventional electrical power generation is achieved using extremely large generating facilities that typically produce heat through nuclear reaction or by burning combustible matter such as coal, oil, or natural gas. The heat is then used to convert water to pressurized steam, and the pressurized steam used to spin an electricity generating turbine. Next, the electricity is transmitted over great distance from this large central plant to the end user. In the transmission and distribution of electrical energy, there are many utility poles that are anchored into the earth, and power lines strung overhead between adjacent utility poles. In view of the essential nature that electricity plays in the modern world, these utility poles are almost always afforded right-of-way to allow the utility companies to access and maintain the lines.
The efficiency of modern photovoltaic cells is very high, and the cost is quite low. Furthermore, the electricity may be generated at or close to the point of consumption, which may provide lower transmission losses and greater power distribution capacity. Consequently, much opportunity exists to generate a substantial portion of electricity required for everyday use through the generation of electricity using sunlight, referred to in technical circles as solar insolation. Unfortunately, there has always been a divide between the capability to produce power from sunlight and the desire to actually install a system.
There have been several barriers to the adoption of photovoltaic systems. One barrier is the cost of installation. Not only do the solar cells need to be purchased, but they must also be installed in a manner that allows them to withstand the vagaries of the environment. Typically this includes wind and ice loading. Even when properly designed, the solar panels may become detached in an exceptional wind storm or hurricane, perpetrating damage to the supporting structure. Furthermore, when the solar cells are mounted to an existing building, the very act of installation can and often does harm the building. For example, a roof-mounted system will have fasteners that penetrate the roof of the structure. Over time, these “holes” in the roof may develop leaks that cause far more damage than the system will return in power savings. Consequently, the installation systems are necessarily expensive, and require expertise that in turn translates into high labor costs.
Yet another barrier has been adverse alteration to the aesthetic appearance of a building. The panels are very difficult to incorporate into the appearance of a building, often detracting therefrom. A homeowner or commercial property owner will often forego the installation purely due to aesthetic factors.
However, a utility pole may also be used to support solar cell arrays. In this case, the photovoltaic array does not detract from the appearance of the pole and transmission line, and the utility pole is already securely anchored into the earth. U.S. Pat. No. 8,466,581 by Kuran, also published as 2010/0327657 and entitled “System and method for utility pole distributed solar power generation,” the teachings and contents which are incorporated herein by reference, shows multiple poles with the one or more PV cells mounted on them, and provides an extensive discussion of the interface between the solar panels and the grid. Unfortunately, the Kuran construction is very exposed, leaving the system vulnerable to wind and ice loading. Furthermore, the panels are oriented for peak power production at or around midday, and so will only produce power for a few hours each day.
In U.S. Pat. No. 8,097,980 by Cyrus et al, entitled “Distributed solar power plant and a method of its connection to the existing power grid,” the teachings and contents which are incorporated herein by reference, another PV system using utility poles is illustrated. This patent fails to describe how the panels are mounted.
Several additional US patents and published applications illustrate solar cells coupled with poles, the teachings and contents which are incorporated herein by reference, including 2013/0322063 by Tittle, entitled “Solar retrofit lighting system”; U.S. Pat. No. 8,029,154 by Myer, entitled “Solar-powered light pole and LED light fixture”; and U.S. Pat. No. 6,060,658 by Yoshida et al, entitled “Pole having solar cells”.
Other US patents and published applications, the teachings and contents which are incorporated herein by reference, illustrate PV panels used to power a light on the pole or other somewhat less relevant concepts, but that nevertheless represent the state of the industry and provide a representation of the level of skill in the field: U.S. Pat. No. 4,200,904 by Doan, entitled “Solar powered street lighting system”; U.S. Pat. No. 4,281,369 by Batte, entitled “Method and apparatus for solar power lighting”; U.S. Pat. No. 4,319,310 by Kingsley, entitled “Solar signs”; U.S. Pat. No. 5,149,188 by Robbins, entitled “Solar powered exterior lighting system”; U.S. Pat. No. 5,155,668 by Tanner et al, entitled “Solar powered lamp utilizing cold cathode fluorescent illumination and method of facilitating same”; U.S. Pat. No. 7,976,180 by Haun et al, entitled “Solar powered rechargeable street light with tamper resistant networkable system”; U.S. Pat. No. 7,980,725 by Yu et al, entitled “Solar energy street lamp structure with air passageway”; U.S. Pat. No. 7,988,320 by Brumels, entitled “Lighting device having adjustable solar panel bracket”; U.S. Pat. No. 7,997,754 by Zhang et al, entitled “Solar component and devices containing the same”; U.S. Pat. No. 8,007,124 by Kim, entitled “Self-generating streetlight”; U.S. Pat. No. 8,097,980 by Cyrus et al, entitled “Distributed solar power plant and a method of its connection to the existing power grid”; U.S. Pat. No. 8,106,593 by Nevins, entitled “Hybrid lighting device”; U.S. Pat. No. 8,215,807 by Brunesti, entitled “Illuminating flagpole assembly”; U.S. Pat. No. 8,246,207 by Chen et al, entitled “LED solar traffic marking panel fitted with integrated dimming controller”; U.S. Pat. No. 8,267,541 by Watanabe et al, entitled “Outdoor illuminating device and illuminating method”; U.S. Pat. No. 8,313,210 by Zheng, entitled “Solar-powered LED indicator lamp”; U.S. Pat. No. 8,342,706 by Zheng, entitled “LED lamp”; 2008/0137327 by Hodulik, entitled “Grid-tied solar streetlighting”; 2013/0118555 by Samuels, entitled “Solar energy collectors and methods for capturing solar energy”; and 2013/0234605 by Burrows, entitled “Hybrid outdoor streetlamp assembly”.
In addition to the foregoing patents, Webster's New Universal Unabridged Dictionary, Second Edition copyright 1983, is incorporated herein by reference in entirety for the definitions of words and terms used herein.